The present invention is to novel intermediates useful in the synthesis of alanine diacetic acid.
Chelants or chelating agents are compounds which form coordinate-covalent bonds with a metal ion to form chelates. Chelates are coordination compounds in which a central metal atom is bonded to two or more other atoms in at least one other molecule or ion, called a ligand, such that at least one heterocyclic ring is formed with the metal atom as part of each ring.
Chelants are used in a variety of applications including food processing, soaps, detergents, cleaning products, personal care products, pharmaceuticals, pulp and paper processing, water treatment, metalworking and metal plating solutions, textile processing solutions, fertilizers, animal feeds, herbicides, rubber and polymer chemistry, photofinishing, and oil field chemistry. Some of these activities result in chelants entering the environment. For example, agricultural uses or detergent uses may result in measurable quantities of the chelants in water.
As chelants may enter the environment from various uses, it would be desirable to have chelants that would readily degrade after use. It would be particularly advantageous to have a chelant which is biodegradable, that is, susceptible to degradation by microbes which are generally naturally present in environments into which the chelants may be introduced.
Alpha alanine diacetic acid (ADA) has been recognized as a chelant for use in a variety of applications. For example, U.S. Pat. Nos. 3,969,257 and 4,120,800 disclose the use of ADA as a perborate stabilizer in laundry detergents and Japanese KOKAI 55-157695, published Dec. 8, 1980 discloses the use of ADA as a builder in detergent compositions to complex with metal ions to reduce the hardness, i.e., free metal ion content, of the water.
Conventional routes for the synthesis of ADA include reacting imidodiacetic acid with a 2-halo propionic acid or by treating alanine with a 2-haloacetic acid. A disadvantage of this route of synthesis is that a salt, such as sodium bromide or sodium chloride is produced. Removal of the produced salt requires relatively expensive procedures such as crystallization, or if carried along with ADA, can cause corrosion of equipment in which such ADA is used.
It would therefore be advantageous to have a novel composition of matter that is useful as an intermediate in the synthesis of ADA which allows ADA to be produced by an improved process in good yields and at high conversions without the formation of a salt that is difficult to remove or that is corrosive to equipment exposed to ADA containing such a salt.